We propose to develop a patient study method for determining local cerebral blood volume (LCBV), local cerebral blood flow (LCBF), local cerebral metabolism (LCM), and other physiologic data localized throughout the brain in three-dimensions using transverse section scanning of radionuclides given intravenously. Once validated, these methods will be applied to enhance the diagnosis in management of patients with brain tumors, stroke, head injury, and metabolic encephalopathies and aid in our understanding of normal physiology in man.